Heretofore, various methods for producing fermented foods analogous or similar to cheese from soybean milk have been proposed. However, it is difficult to obtain fermented foods which are comparable to cheese made from cow's milk having suitable properties including appropriate flavor, composition and touch. Such fermented foods are only analogous to natural foods, and the exploitation thereof has been limited to the trial stage and has not reached any practical level.
One reason that soybean milk has not been practically exploited is that it is different from cow's milk in its requirements for heating, lactic fermentation and curd preparation and it has a different compositional structure during ripening. For that reason, the product from soybean milk has been inferior to the existing cheese made from cow's milk in hardness, elasticity and flavor. In other words, a product produced from soybean milk has been inferior to a product made from cow's milk because the curds obtained from soybean milk have a much higher water content and a composition unsuitable for ripening and the soybean curds do not gently or smoothly ripen which results in insufficient brewing to produce the desired flavor. Therefore, considerable studies have been heretofore devoted to reducing the water content of the curds, the selection of ripening starters, the combination of lactic acid bacteria with other microorganisms, the method of ripening and flavor improvements, but these studies have for the most part failed to obtain sufficient flavor.
Low-temperature ripening has been previously attempted in order to improve the flavor. However, even though ripening was carried out in a low-temperature region for a prolonged period with the use of lactic acid bacteria alone for the preparation of quasi-cheese foods from soybean milk, the degree of ripening was so low that the resulting product was degraded in its physical properties, flavor and color tone. Thus, it has been difficult to obtain any edible quasi-cheese foods.